It is the aim of this project to thoroughly examine the solution properties of the polysaccharide, levan from dental plaque. The size, shape, molecular weight, molecular weight distribution, branching, etc. will be explored for the various fractions of levan obtained by fractionation and from hydrolysis. Since levan is essentially a non- charged macromolecule, its solution properties may not be drastically affected by ionic strength. However, pH can influence hydrolytic cleavage of the chain, and accordingly, samples will also be examined as a function of pH. Although levan is souble in water, nevertheless, when present in dental plaque, it can not be easily washed away. This could either suggest complexation of the levan to some substance (e.g., protein, other polysaccharides calcium etc. and/or inability to diffuse through the plaque. Therefore, and additional aim of this project is to also examine some binding properties of levan. It is the further aim of this project to conduct parallel studies on those polysaccharides produced from pure strains of various bacteria, e.g., Streptococcus sanguis, S. salivarius, S. mitis, S. mutans, and Odontomyces viscosus, to unequivocally establish differences, if any, in physico-chemical properties of the levan produced among the different bacteria. Additionally, properties of levan produced by a given bacterial strain as a function of pH will be examined.